According to several top professional golfers, when you have a stable lower body you can really drive off your rear leg late in the downswing. This so-called ‘springboard effect’ is supposed to supply extra clubhead speed and ultimately more distance.” However this recommendation is contrary to what occurs in the swing – and what most pro golfers do late in the downswing.
When do drive off the rear leg, you initiate the downswing. In other words, you push your hips forward so that they come through early in the swing to set up the chain actions of the upper body that follow in sequence. If instead, you have already turned the shoulders and the arms are bringing the clubhead down when you drive off the rear leg, it will contribute very little force to the hit.
Tiger Woods and Dave Duval are classic examples of getting the hips cleared early in the swing before the arms begin their action. However, keep in mind that the arms may be in motion because the shoulders bring them around. This does not mean that you initiate the arm action; since it happens later when the hands are about shoulder high.